1. Field of the Invention
The present invention relates to a powered toothbrush, and more particularly, to a brush section having a partially disk-shaped carrier that includes one or more tooth care elements (i.e., bristles or elastomeric members) extending therefrom to provide increased contact with the teeth and/or the oral gingival tissue for enhanced massaging thereof.
2. Description of the Related Art
Toothbrushes provide many oral hygiene benefits. For example, toothbrushes remove plaque and food debris to help avoid tooth decay and disease. They remove stained pellicle from the surface of each tooth to help whiten the teeth. Also, the bristles combined with the brushing motion will massage the gingival tissue for stimulation and increased health of the tissue.
Powered toothbrushes have been available for some time. Powered toothbrushes have advantages over manual (non-powered) toothbrushes in that they impart movement to the bristles at much higher speeds than possible manually. They also may impart different types and directions of motion. These motions, generally in combination with manual movement of the toothbrush by the user, provide superior cleaning than manual toothbrushes. Typically, powered toothbrushes are powered by disposable or rechargeable batteries that power an electric motor that in turn drives the toothbrush head.
Known powered toothbrushes include a brush head with a bristle carrier portion that rotates, oscillates or vibrates in some manner so as to clean the teeth. The bristles, which typically comprise bristle tufts, are generally uniform with one end fixed into the bristle carrier portion and the other end free to contact the surface of the teeth while brushing. The free ends of the various tufts present a surface envelope that is capable of some deformation when the bristles bend. When in contact with the surface to be brushed, the bristles may deform so that the surface envelope tends to conform to the complex surface of the teeth. Human teeth generally lie in a “C” shaped curve within the upper and lower jaws. Individual teeth often have extremely complex surfaces, with areas that may be flat, concave, or convex. The more precise conformation between the bristles and the tooth surface, the more effective the toothbrush may be in cleaning, whitening and stimulating.
Known powered toothbrushes typically arrange the bristles in a compact conical or cylindrical pattern on a generally circular, disk-shaped bristle carrier. The powered toothbrush heads are traditionally compact, generally oval in shape and the heads are produced with a flat trimmed bristle pattern. Alternatively, other head shapes and bristle patterns are available.
One example of a powered toothbrush known in the art is depicted in U.S. Pat. No. 5,625,916 to McDougall, which is hereby incorporated by reference in its entirety. The toothbrush shown in McDougall has a disc-shaped bristle carrier. The bristle carrier, and thus the bristles, are driven in a vibrating or oscillating manner. This type of toothbrush is described herein with reference to FIGS. 1A-1C. A toothbrush 5 comprises a handle portion 10 at a proximal end of the toothbrush 5 and a head 11 at a distal end of the toothbrush 5. The handle portion 10 has compartments for containing a powered motor 14 and batteries 15 and 16. The head 11 includes a generally circular bristle holder (carrier) 13. A rotatable shaft 12 extends from the motor 14 to the head 11. A shaft coupling 17 may be located along the shaft 12 and configured to provide for the shaft 12 to be separated at a point between the motor 14 and the head 11. This permits the shaft to be removed from the toothbrush 5, e.g., for cleaning, servicing, or replacement.
The head 11 includes a post 18 that provides a rotational pivot axis for the bristle holder 13 containing bristle tufts 19. The distal end of the shaft 12 has a journal or offset 20 that is radially displaced from the longitudinal axis of the shaft 12. The bristle holder 13 has a slot 22 that receives the offset 20. The offset 20 and slot 22 are configured so as to be oriented toward the intersection of the shaft 12 axis and the longitudinal axis of the post 18. When the motor 14 rotates the shaft 12, the motion of the offset 20 defines a circle about the shaft 12 axis and drivingly engages the slot 22 such that the bristle holder 13 vibrates or oscillates about the post 18 axis through a rotational angle A. The rotational angle A is defined by the displacement of the offset 20 from the shaft 12 axis relative to the diameter of the bristle holder 13.
Powered toothbrushes such as those described immediately above provide advantages over manual toothbrushes, but are subject to various limitations because of the relatively small head size. Providing a rotating or oscillating bristle holder (carrier) with a typical oblong or oval toothbrush head constrains the size of the moving bristle holder, and consequently the area of bristles available for teeth cleaning. Also, when the bristles are placed in contact with the teeth during brushing, there is less bristle contact with adjacent areas, such as the gums, resulting in minimal stimulation of the gingival tissue.
One attempt to overcome the limitations of a small powered bristle area is shown in U.S. Pat. No. 6,000,083 to Blaustein et al. The toothbrush in Blaustein et al. has a bristle area and pattern similar to a manual toothbrush, but an area of the bristles has simply been replaced by a powered bristle section. The result is that the head has a powered or moving bristle section and static bristle section. The limitation of the toothbrush of Blaustein et al. is that the static bristle section provides no better cleaning, whitening or stimulation than a manual toothbrush.
International Application No. PCT/EPO1/07615 of Braun GmbH discloses a powered toothbrush with two separate, movable bristle sections. Each bristle section may have a different range and type of motion. The toothbrush of Braun, however, discloses only one powered bristle section. The other unpowered bristle section moves due to a resonance effect imparted by the frequency of the movement of the first bristle section.
This free resonance presents a number of difficulties. First, because any contact between the bristle parts will dampen or cancel any resonance of the unpowered bristle part, the unpowered bristle section “floats” separately from the powered bristle section and the rest of the toothbrush head. This necessitates separation or gaps between them. These gaps expose the internal workings of the head to foreign matter such as water, saliva, toothpaste, and food particles. This foreign matter may interfere with the workings of the unpowered bristle head. For example, the unpowered bristle part is spring-loaded to assist its resonance. Foreign matter may accumulate on or around the spring, interfering with its function. In addition, food particles may remain in the head and may fester and host microorganisms, which are undesirable if not potentially harmful when introduced directly into the mouth.
Another limitation of such a design is that movement of the unpowered bristle section may be damped by contact with the teeth, or lessened when the frequency of the powered section shifts from the resonance frequency. This can occur due to pressure imparted against the powered bristle section by the teeth or gums during brushing. An additional limitation is that the energy imparted to the unpowered bristle section is only a portion of the energy input into the powered section. Therefore, the unpowered bristle section is less effective in cleaning than the powered section, limiting the overall effectiveness of the toothbrush.
Thus, there is a need in the art for a powered toothbrush with increased effectiveness through a larger area of powered or driven bristles than known powered toothbrushes. There is also a need for a toothbrush having increased whitening and stimulation than known toothbrushes. There is a further need for such improved toothbrushes to be comparable in manufacturing and purchasing costs as known powered toothbrushes.